Method and system of a dynamic high-availability mode based on current wide area network connectivity

ABSTRACT

In one aspect, a computer-networking method useful for implementing dynamic high-availability (HA) mode based on current wide area network (WAN) connectivity, comprising the steps of: providing a first edge device of a local area network (LAN) with the WAN; providing a second edge device of the LAN with the WAN; and synchronizing a state of plurality of links with the WAN that are connected to the first edge device and the second edge device.

CLAIM OF PRIORITY

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/583,733, titled METHOD AND SYSTEM OF A HIGH AVAILABILITYENHANCEMENTS TO A COMPUTER NETWORK filed on 09 Nov. 2017. Thisapplication is hereby incorporated by reference in its entirety.

BACKGROUND

FIG. 1 (prior art) illustrates an example High Availability (HA) networktopology 100, according to some embodiments. There may be two keydeficiencies in HA network topology 100 which are addressed by theenhancements in FIGS. 2-10. A first deficiency can include therequirement of a switch on the WAN side of the HA pair (e.g. first edgedevice 112 and second edge device 114). The WAN can include MPLS 102 andInternet 108. A single switch may introduce a single point of failure inactuality two WAN-side switches are required for full redundancy. Theaddition of two switches (e.g. switches 116 and 120) may increases thecomplexity of the insertion without providing any real benefit. Afterthe installation of an Edge Router, a customer may be responsible forthe switch.

Additionally, unpredictable behavior in split brain scenarios may ariseTypically the switches may run a Spanning Tree Protocol to prevent loopsin the network. If both devices go active (e.g. HA cable 118 isdisconnected), then each switch may block a different device, causing atotal loss of traffic through the pair.

BRIEF SUMMARY OF THE INVENTION

In one aspect, a computer-networking method useful for implementingdynamic high-availability (HA) mode based on current wide area network(WAN) connectivity, comprising the steps of: providing a first edgedevice of a local area network (LAN) with the WAN; providing a secondedge device of the LAN with the WAN; and synchronizing a state ofplurality of links with the WAN that are connected to the first edgedevice and the second edge device.

The computerized method can further detect that the plurality of linksare connected to the second edge device and not the first edge device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 (prior art) illustrates an example High Availability (HA) networktopology, according to some embodiments.

FIG. 2 illustrates an example network topology with a switch on a WANside of a HA pair, according to some embodiments.

FIG. 3 illustrates an example network topology, according to someembodiments.

FIGS. 4 A-B illustrates a network topology illustrating a first use casethat covers edge device with shared links, according to someembodiments.

FIGS. 5 A-B illustrate network topology illustrating a second use casethat includes a scenario where there is only one link connected to eachedge device (e.g. edge devices with unique links), according to someembodiments.

FIG. 6 illustrates another example network topology, according to someembodiments.

FIG. 7 illustrates another example network topology with an active LAN,according to some embodiments.

FIG. 8 illustrates yet another example network topology, according tosome embodiments.

FIG. 9 illustrates an example communication exchange process, accordingto some embodiments.

FIG. 10 illustrates an example process for implementing dynamic HA modebased process on current WAN connectivity, according to someembodiments.

FIG. 11 depicts an exemplary computing system that can be configured toperform any one of the processes provided herein.

FIG. 12 illustrates an example process for providing dynamic HA modebased on current WAN connectivity, according to some embodiments.

The Figures described above are a representative set, and are notexhaustive with respect to embodying the invention.

DESCRIPTION

Disclosed are a system, method, and article of manufacture for dynamichigh-availability mode based on current wide area network connectivity.The following description is presented to enable a person of ordinaryskill in the art to make and use the various embodiments. Descriptionsof specific devices, techniques, and applications are provided only asexamples. Various modifications to the examples described herein can bereadily apparent to those of ordinary skill in the art, and the generalprinciples defined herein may be applied to other examples andapplications without departing from the spirit and scope of the variousembodiments.

Reference throughout this specification to “one embodiment,” “anembodiment,” ‘one example,’ or similar language means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the presentinvention. Thus, appearances of the phrases “in one embodiment,” “in anembodiment,” and similar language throughout this specification may, butdo not necessarily, all refer to the same embodiment.

Furthermore, the described features, structures, or characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. In the following description, numerous specific details areprovided, such as examples of programming, software modules, userselections, network transactions, database queries, database structures,hardware modules, hardware circuits, hardware chips, etc., to provide athorough understanding of embodiments of the invention. One skilled inthe relevant art can recognize, however, that the invention may bepracticed without one or more of the specific details, or with othermethods, components, materials, and so forth. In other instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring aspects of the invention.

The schematic flow chart diagrams included herein are generally setforth as logical flow chart diagrams. As such, the depicted order andlabeled steps are indicative of one embodiment of the presented method.Other steps and methods may be conceived that are equivalent infunction, logic, or effect to one or more steps, or portions thereof, ofthe illustrated method. Additionally, the format and symbols employedare provided to explain the logical steps of the method and areunderstood not to limit the scope of the method. Although various arrowtypes and line types may be employed in the flow chart diagrams, andthey are understood not to limit the scope of the corresponding method.Indeed, some arrows or other connectors may be used to indicate only thelogical flow of the method. For instance, an arrow may indicate awaiting or monitoring period of unspecified duration between enumeratedsteps of the depicted method. Additionally, the order in which aparticular method occurs may or may not strictly adhere to the order ofthe corresponding steps shown.

DEFINITIONS

Example definitions for some embodiments are now provided.

Address Resolution Protocol (ARP) is a communications protocol used fordiscovering the link layer address associated with a given Internetlayer address, a critical function in the Internet protocol suite.

CE router (customer edge router) can be a router located on the customerpremises that provides an Ethernet interface between the customer's LANand the provider's core network. CE routers can be a component in anMPLS architecture.

Dynamic tunneling can refer to MultiPath tunnels (i.e. paths) that areestablished on-demand between two endpoints when there is VPN traffic tobe sent between two Edges, and torn down after VPN traffic is completed.

Edge device can be a device that provides an entry point into enterpriseor service provider core networks. An edge device can be softwarerunning in a virtual machine (VM) located in a branch office and/orcustomer premises.

Gateway can be a node (e.g. a router) on a computer network that servesas an access point to another network.

LAN is a local area network, a computer network covering a small localarea.

Multiprotocol Label Switching (MPLS) is a type of data-carryingtechnique for high-performance telecommunications networks. MPLS directsdata from one network node to the next based on short path labels ratherthan long network addresses, avoiding complex lookups in a routingtable. The labels identify virtual links (paths) between distant nodesrather than endpoints. MPLS can encapsulate packets of various networkprotocols.

Orchestrator can include a software component that provides multi-tenantand role based centralized configuration management and visibility.

Split brain can refer to data or availability inconsistenciesoriginating from the maintenance of two separate data sets with overlapin scope, either because of servers in a network design, or a failurecondition based on servers not communicating and synchronizing theirdata to each other.

Tunneling protocol can allow a network user to access or provide anetwork service that the underlying network does not support or providedirectly.

Wide area network (WAN) is a telecommunications network or computernetwork that extends over a large geographical distance.

Virtual private network (VPN) can extend a private network across apublic network, such as the Internet. It can enable users to send andreceive data across shared or public networks as if their computingdevices were directly connected to the private network, and thus benefitfrom the functionality, security and management policies of the privatenetwork.

Additional example definitions are provided herein.

EXAMPLES SYSTEMS AND PROCESSES

It is noted that the following systems and methods are backwardscompatible with existing HA deployments, thus requiring no changes toexisting user interfaces.

FIG. 2 illustrates an example network topology 200 with a switch on aWAN side of a HA pair, according to some embodiments. It is noted thatan HA switch may no longer be required on the WAN side of the HA pair.Instead, a customer can connect one or more WAN links to each of theedge devices 212, 214 in the pair (e.g. via customer router 206 and/ormodem 210). The devices can then synchronize their connected interfacestatus. If the active edge device 212 or both edge devices 212, 214 havethe same interface connected, then this can be initiated directly. Ifonly a standby edge 214 has an interface connected, then connectivitycan be enabled through the standby edge 214 by bridging the tunnels(e.g. tunnel B 222 to tunnel A 220) across the HA cable 218 and out thepeer WAN link.

Now that each of the edge devices 212, 214 has its own individual set ofWAN connections, a split-brain scenario can be easily determined by agateway which has a full view of what is happening from the perspectiveof both edge devices 212, 214.

It is noted that each of the edge devices 212, 214 has its ownindividual set of WAN connections, a split-brain scenario can bedetermined by the Gateway. The Gateway can have a full view of the stateof each of the edge devices 212, 214 from the perspective of both edgedevices 212, 214.

FIG. 3 illustrates an example network topology 300, according to someembodiments. As shown, a high availability (HA) cable 318 can bedisconnected. Each of the edge devices 312, 314 can establish a tunnel(e.g. tunnels A and B 320, 322) directly with a gateway system. Thegateway system can determine that an edge is connected, active andpassing traffic. The gateway system can open a tunnel to the secondedge. The gateway system can signal to the edge to go to standby on thelocal LAN 318. If it is detected that the edge loses connectivity, thenthe gate system can signal to the other edge to become the active edge.Network topology 300 can be used to implement process 1000 providedbelow.

A dynamic HA mode based on current WAN connectivity can be implemented.It is noted that a WAN switch is no longer required for HA deploymentsas links may be connected to individual edge devices. This can beaccomplished by leveraging the link state which is already synchronizedbetween the edge devices and, using a standby edge as a virtual switchto reach links attached to the standby edge only.

FIGS. 4 A-B illustrates a network topology 400 illustrating a first usecase that covers edge device with shared links (e.g. backwardscompatibility), according to some embodiments. More specifically, FIG.4A illustrates an initial state and FIG. 4B illustrates an HA failoverstate. The first edge device 412 can have two links connected while thesecond edged device 414 only has one link connected. Accordingly, thefirst edge device 412 can be the preferred edge and by default theactive edge. As the first edge device 412 has local connectivity to bothlinks, both tunnels (e.g. tunnels A and B 420 422) can be initiateddirectly from the first edge device 412. If there is an HA failover, thesecond edge device 414 can only have access to the link that is directlyconnected to it.

FIGS. 5 A-B illustrate network topology 500 illustrating a second usecase that includes a scenario where there is only one link connected toeach edge device (e.g. edge devices with unique links), according tosome embodiments. More specifically, FIG. 5A illustrates an initialstate and FIG. 5B illustrates an HA failover state. The first edgedevice 512 can have MPLS 502 connected and the second edge device 514has the public internet 508 connected. Accordingly, the first edgedevice 512 the preferred edge and by default the active edge. As thefirst edge device 512 does not have local connectivity to the internetlink, that tunnel (e.g. tunnel B 522) can be initiated by proxyingthrough the second edge device 514. If there is an HA failover, thesecond edge device 514 can only have access to a link with which it isdirectly connected.

FIG. 6 illustrates another example network topology 600, according tosome embodiments. As noted in FIGS. 5 A-B, an edge device can beconnected to two WAN links. A first WAN link can be connected locally,and a second WAN link can be proxied via the second edge device 614. Forsimplicity this can be presented as two public Internet links, howeverit could also be accomplished with hybrid links, as long as, a privateWAN link can reach a gateway (e.g. partner gateway deployment, SD-WANservice reachable enabled, etc.).

FIG. 7 illustrates another example network topology 700 with an activeLAN, according to some embodiments. Gateway 704 can have a pre-existingconnection to a first edge device 712. Edge device 712 can be thepreferred active edge. Second edge device 714 (e.g. with the samelogical ID) can be connected on a different WAN link. Gateway 704 canmaintain tunnel B 722 as an active tunnel for future use. Gateway 704can signal the second edge device 714 to go into standby mode on theLAN. This process can be used to logically prevent the split-brainscenario from occurring. LAN can connect with edge devices 712, 714 viaactive LAN that responds to ARP 722. FIG. 8 illustrates yet anotherexample network topology, according to some embodiments.

FIG. 9 illustrates an example communication exchange process 900,according to some embodiments. In step 902, gateway receives MP_INIT,but sees a first edge device is active and sets GO_STANDBY flag inMP_INIT_ACK. In step 904, edge receives GO_STANDBY flag in MP_INIT_ACK,goes back into standby mode on the LAN, but keeps the tunnel establishedby gateway. In step 906, the gateway receives confirmation that a secondedge device is in standby mode. If first edge device tunnel(s) becomeunavailable, then the second edge device can be signaled to becomeactive. Following the exchange, the split-brain scenario can have beencleared. For example, Gateway receives tunnel initiation request from714 but sees that 712 is already active. The Gateway responds to thetunnel initiation request but sets a flag in the response indicatingthat the 714 device can go into a standby mode on the LAN.

FIG. 10 illustrates an example process for implementing dynamic HA modebased process 1000 on current WAN connectivity, according to someembodiments. In step 1002, the HA cable can be disconnected. In step1004, the second edge device established a communicative networkconnection directly with a gateway system. In step 1006, the gatewaydetermines that another first edge device is active and passing networktraffic to a LAN. In step 1008, the gateway opens a tunnel with secondedge device and signals to second edge device to go on standby mode. Instep 1010, if the first edge device loses connectivity then gatewaysignals to second edge device to take over as the active edge.

FIG. 11 depicts an exemplary computing system 1100 that can beconfigured to perform any one of the processes provided herein. In thiscontext, computing system 1100 may include, for example, a processor,memory, storage, and I/O devices (e.g., monitor, keyboard, disk drive,Internet connection, etc.). However, computing system 1100 may includecircuitry or other specialized hardware for carrying out some or allaspects of the processes. In some operational settings, computing system1100 may be configured as a system that includes one or more units, eachof which is configured to carry out some aspects of the processes eitherin software, hardware, or some combination thereof.

FIG. 11 depicts computing system 1100 with a number of components thatmay be used to perform any of the processes described herein. The mainsystem 1102 includes a motherboard 1104 having an I/O section 1106, oneor more central processing units (CPU) 1108, and a memory section 1110,which may have a flash memory card 1112 related to it. The I/O section1106 can be connected to a display 1114, a keyboard and/or other userinput (not shown), a disk storage unit 1116, and a media drive unit1118. The media drive unit 1118 can read/write a computer-readablemedium 1120, which can contain programs 1122 and/or data. Computingsystem 1100 can include a web browser. Moreover, it is noted thatcomputing system 1100 can be configured to include additional systems inorder to fulfill various functionalities. Computing system 1100 cancommunicate with other computing devices based on various computercommunication protocols such a Wi-Fi, Bluetooth® (and/or other standardsfor exchanging data over short distances includes those usingshort-wavelength radio transmissions), USB, Ethernet, cellular, anultrasonic local area communication protocol, etc.

FIG. 12 illustrates an example process 1200 for providing dynamic HAmode based on current WAN connectivity, according to some embodiments.In step 1202, process 1200 can synchronize the state of links that areconnected to each individual edge. In step 1204, if the link isconnected to first edge device only (and/or both edges in some exampleembodiments), then process 1200 can initiate tunnels locally. In step1206, if a link is connected to second edge device and not first, thenprocess 1200 can initiate tunnels via a proxy over HA cable. Dynamic HAMode election can be used to determine whether there is a WAN Switchproviding connectivity to the same link via both edge devices orseparate links connected to independent edge devices, and thenautomatically initiating tunnels locally or via proxy based onauto-detecting this.

CONCLUSION

Although the present embodiments have been described with reference tospecific example embodiments, various modifications and changes can bemade to these embodiments without departing from the broader spirit andscope of the various embodiments. For example, the various devices,modules, etc. described herein can be enabled and operated usinghardware circuitry, firmware, software or any combination of hardware,firmware, and software (e.g., embodied in a machine-readable medium).

In addition, it can be appreciated that the various operations,processes, and methods disclosed herein can be embodied in amachine-readable medium and/or a machine accessible medium compatiblewith a data processing system (e.g., a computer system), and can beperformed in any order (e.g., including using means for achieving thevarious operations). Accordingly, the specification and drawings are tobe regarded in an illustrative rather than a restrictive sense. In someembodiments, the machine-readable medium can be a non-transitory form ofmachine-readable medium.

1. A computer-networking method useful for implementing dynamichigh-availability (HA) mode based on current wide area network (WAN)connectivity, comprising the steps of: providing a first edge device ofa local area network (LAN) with the WAN; providing a second edge deviceof the LAN with the WAN; and synchronizing a state of plurality of linkswith the WAN that are connected to the first edge device and the secondedge device.
 2. The computer-networking method of claim 1 furthercomprising: detecting that the plurality of links are connected to thesecond edge device and not the first edge device.
 3. Thecomputer-networking method of claim 2 further comprising: initiating atunneling protocol via a proxy device over HA cable between the firstedge device and the second edge device.
 4. The computer-networkingmethod of claim 1 further comprising: detecting that the plurality oflinks are connected to only the first edge device.
 5. Thecomputer-networking method of claim 1 further comprising: initiating thetunnel protocol at a local location.
 6. A computer system useful forimplementing dynamic high-availability (HA) mode based on current widearea network (WAN) connectivity, comprising: a processor; a memorycontaining instructions when executed on the processor, causes theprocessor to perform operations that: provide a first edge device of alocal area network (LAN) with the WAN; provide a second edge device ofthe LAN with the WAN; synchronize a state of plurality of links with theWAN that are connected to the first edge device and the second edgedevice; detect that the plurality of links are connected to the secondedge device and not the first edge device; and initiate a tunnelingprotocol via a proxy device over HA cable between the first edge deviceand the second edge device.
 7. A computer system useful for implementingdynamic high-availability (HA) mode based on current wide area network(WAN) connectivity, comprising: a processor; a memory containinginstructions when executed on the processor, causes the processor toperform operations that: provide a first edge device of a local areanetwork (LAN) with the WAN; provide a second edge device of the LAN withthe WAN; synchronize a state of plurality of links with the WAN that areconnected to the first edge device and the second edge device; detectthat the plurality of links are connected to only the first edge device;and initiate the tunnel protocol at a local location.